Using lsqcurvefit with a function that contains a for loop

I want to fit Fick's Law for diffusion in a sphere using lsqcurvefit to experimental data.

The equation is an infinite series of the form

y = 1- sum((A/n^2 * exp(-B*n^2*t - t0))

I would like to create a function which sums the first 100 n terms using a for loop and then use lsqcurvefit to adjust parameter B to fit the experimental mass versus time data.

I know how to use lsqcurvefit, I just want to know how to fit this equation without adding the first 100 etc terms manually in the function file.

Thanks for your help,

Jon

Answer 1

[Matt J]

No idea why you think you need a for loop. The SUM command will work just fine,

 n=1:100;

 y = 1- sum((A./n.^2 .* exp(-B*n.^2*t - t0));